Preliminary Study on Diversity and Abundance of ...
6
PertanikaJ. Trop. Agric. Sci. 24(1): 43 - 48 (2001) ISSN: 1511-3701 © Universiti Putra Malaysia Press Preliminary Study on Diversity and Abundance of Ichneumonids and Braconids (Insecta: Hymenoptera) at the Ayer Hitam Forest Reserve IDRIS, A.lll, SAJAP, A. NOOR FARIKHA, YAAKOB, A. and M. Y I School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia 2Faculty of Forestry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Keywords: Diversity, abundance, Hymenoptera, Ayer Hitam Forest Reserve ABSTRAK Satu kajian awal tentang kepelbagaian dan kelimpahan ichneumonid dan braconid (Insecta: Hymenoptera) di Hutan Simpan Ayer Hitam (AHFR), Universiti Putra Malaysia telah dij'alankan dari 4- 11 April 2000. Hasil kajian ini menunjukkan bahawa AHFR didiami oleh pelbagai spesies ichneumonid dan braconid. Secam keseluruhannya, didapati bahawa spesies ichneumonid adalah hampir dua kali lebih melimpah dan pelbagai berbanding braconid. Walau bagaimanapun, kedua-dua kumpulan serangga ini mempunyai kepelbagaian spesies yang lebih tinggi dan signijikan di bahagian tengah hutan berbanding di kawasan pinggir hutan. Dua lagi tambahan subfamili ichneumonid (Adelognathinae dan Orthopelmatinae) untuk Malaysia Lelah ditemui dari hutan ini. ABSTRACT A preliminary study on diversity and abundance of ichneumonids and braconids (Insecta: Hymenoptera) oj Ayer Hitam Forest Reserve (AHFR) oj Universiti Putra Malaysia was conducted Jrom 4- 11 April 2000. Results showed that AHFR houses a variety oj ichneumonid and braconid species. Generally, the ichneumonids were nearly twice as abundant and diverse than bra con ids. However, both insect groups were signijicantly more diverse in the middle than in the Jorest fringes. Two more additions of ichneumonid subJamilies (Adelognathinae and Orthopelmatinae) for Malaysia were discovered from this Jorest. INTRODUCTION Insects are the most abundant animals on earth and two-thirds of insects inhabit the tropical rain forest. In Peninsular Malaysia, majority of these insects occupy the lowland forests. These forests provide habitats for thousands of insect species that are functionally important to the forest ecosystems. Insects can be pollinators, decomposers, herbivores, predators or para- sitoids. Most parasitoids are in the order of Hymenoptera. They use or parasitize other insects for reproduction. As such, they are important regulators of other insect populations, mostly herbivores feeding on various parts of plants. In recent years however, the rate of deforestation in the lowland forests is rather alarming. The destruction of natural habitats due to logging and development pose the greatest threat to insect communities in the forests. Since the parasitoid reproduction depends on other insects, their own population and role will be severely affected by the reduction of host population as a consequent of habitat destruction. In view of the changing ecosystem of Ayer Hitam Forest Reserve and its vicinity, a study on the diversity of Ichneumonids and Braconids, the two important group of parasitic Hymenoptera was conducted. Presently, scanty information is available on these in Malaysia except those of Idris (1996a and 1996b), Idris and Nur Azura (1998) and Nor Azura and Idris (1998) .
Transcript of Preliminary Study on Diversity and Abundance of ...
PertanikaJ. Trop. Agric. Sci. 24(1): 43 - 48 (2001) ISSN: 1511-3701
© Universiti Putra Malaysia Press
Preliminary Study on Diversity and Abundance of Ichneumonids and Braconids (Insecta: Hymenoptera) at
the Ayer Hitam Forest Reserve
IDRIS, A.lll, SAJAP, A. S~, NOOR FARIKHA, H~., YAAKOB, A. B~ and M. Y RUSI.AN~
I School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
2Faculty of Forestry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
Keywords: Diversity, abundance, Hymenoptera, Ayer Hitam Forest Reserve
ABSTRAK
Satu kajian awal tentang kepelbagaian dan kelimpahan ichneumonid dan braconid (Insecta: Hymenoptera) di Hutan Simpan Ayer Hitam (AHFR), Universiti Putra Malaysia telah dij'alankan dari 4 - 11 April 2000. Hasil kajian ini menunjukkan bahawa AHFR didiami oleh pelbagai spesies ichneumonid dan braconid. Secam keseluruhannya, didapati bahawa spesies ichneumonid adalah hampir dua kali lebih melimpah dan pelbagai berbanding braconid. Walau bagaimanapun, kedua-dua kumpulan serangga ini mempunyai kepelbagaian spesies yang lebih tinggi dan signijikan di bahagian tengah hutan berbanding di kawasan pinggir hutan. Dua lagi tambahan subfamili ichneumonid (Adelognathinae dan Orthopelmatinae) untuk Malaysia Lelah ditemui dari hutan ini.
ABSTRACT
A preliminary study on diversity and abundance of ichneumonids and braconids (Insecta: Hymenoptera) oj Ayer Hitam Forest Reserve (AHFR) oj Universiti Putra Malaysia was conducted Jrom 4 - 11 April 2000. Results showed that AHFR houses a variety oj ichneumonid and braconid species. Generally, the ichneumonids were nearly twice as abundant and diverse than braconids. However, both insect groups were signijicantly more diverse in the middle than in the Jorest fringes. Two more additions of ichneumonid subJamilies (Adelognathinae and Orthopelmatinae) for Malaysia were discovered from this Jorest.
INTRODUCTION
Insects are the most abundant animals on earth and two-thirds of insects inhabit the tropical rain forest. In Peninsular Malaysia, majority of these insects occupy the lowland forests. These forests provide habitats for thousands of insect species that are functionally important to the forest ecosystems. Insects can be pollinators, decomposers, herbivores, predators or para sitoids. Most parasitoids are in the order of Hymenoptera. They use or parasitize other insects for reproduction. As such, they are important regulators of other insect populations, mostly herbivores feeding on various parts of plants.
In recent years however, the rate of deforestation in the lowland forests is rather
alarming. The destruction of natural habitats due to logging and development pose the greatest threat to insect communities in the forests. Since the parasitoid reproduction depends on other insects, their own population and role will be severely affected by the reduction of host population as a consequent of habitat destruction. In view of the changing ecosystem of Ayer Hitam Forest Reserve and its vicinity, a study on the diversity of Ichneumonids and Braconids, the two important group of parasitic Hymenoptera was conducted. Presently, scanty information is available on these in Malaysia except those of Idris (1996a and 1996b), Idris and Nur Azura (1998) and Nor Azura and Idris (1998) .
IDRIS, A.B, SAJAP, A. S, NOOR FARIKHA, H., YAAKOB, A. Band M. Y RUSlAN
MATERIALS AND METHODS
The study was conducted at Ayer Hitam Forest Reserve (AHFR) , Puchong, Selangor, about 20 km southwest of Kuala Lumpur and 6 km from Universiti Putra Malaysia (UPM), Serdang Campus, Selangor, Malaysia, at latitudes between 20· 57' N to 30· 04' N and longitudes 101· 38'E to 101· 41'E. The AHFR is an undulating lowland dipterocarp forest ranging from 15 m to 157 m above sea level, managed as a forest reserve by the Forest Office of Central Selangor and was selectively logged between 1936 and 1965 (Mohamad Zakaria and Rahmat Topani 1999). The study sites were located within compartments 1, 2, 12, 13, 14 and 15 of AHFR that has been leased to UPM for 80 years under an agreemen t between Universiti Putra Malaysia and the state government of Selangor.
Two transects were established within the compartments, both were parallel to each other and 200 m apart. There were three sampling points (= treatments) chosen along each transect across the compartments viz., two each at both ends and one in middle. The distance between the points was between 200 and 250 m, and 30 - 50 m from the outer sampling point to forest edge. A total of six malaise traps were used and one trap was placed at each sampling point beginning 4 until 11 September 2000. Traps were left in the forest for eight days before insects were collected and brough t to the laboratory for sorting and identification. The specimen identification was made based on Wahl and Sharkey (1993) and Townes and Chiu (1970).
In reducing error and getting a more representative data, the insects collected from similar sampling point of two transects were pooled before analysis. Data were analyzed using GW Basic program to get differential species diversity between sampling points (Robinson, 1991) while X2 was used to analyze differences in species and individual abundance among sampling points
RESULTS AND DISCUSSION
Abundance
The ichneumonids and braconids collected are shown in Tables 1 and 2. There were eight ichneumonid subfamilies collected viz., Cryptinae, Anomaloninae, Cremastinae, Adelognathinae, Diplazontinae, Orthopelma-
tinae, Pimplinae, Collyriinae and the seven braconid subfamilies include Agathidinae, Rogadinae, Microgastrinae, Gnamptodontinae, Opiinae, Cheloninae and Doryctinae. A total of 38 morphospecies and 95 individual ichneumonids were collected. The braconids on the other hand had only 14 morphospecies and 27 individuals (Table 2),3 - 4 times less abundant than ichneumonid. Braconids also seemed to be less abundant than ichneumonids in the Permanent Forest Reserve of Universiti Kebangsaan Malaysia (PFR-UKM) (ldris 1996b). As such, results of this study tend to disagree wi th universal claim that in tropical regions braconids are more abundant than ichneumonids (Noyes 1989, La Salle and Gauld 1993).
Of the eight ichneumonid subfamilies collected, the cryptine had the most numbers of morphospecies (22) and individuals (58) as compared with other subfamilies and morpho species numbered 22, seemed to be the most abundant in AHFR (Table 1). This tends to agree with what was reported by Wahl and Sharkey (1993) as the majority of cryptine species are generalist and/or idiobiont parasitoid having wide host ranges irrespective of habitats. The morpho-species numbered 21 (Table 1) seemed to occur at all sampling points, indicating they are the least group that could be severely affected by habitat disturbances. As for braconids, however, no single subfamily seemed to have more number ofmorphpospecies over the others (Table 2). This indicates that AHFR does not have much resource to support braconid populations.
Although the collection was made for a period of one week, this study was successful in adding two more ichneumonid subfamilies for Malaysia, Le., Adelognathinae and Ortho pelmatinae, from 18 as listed by Idris (2000) to 20 subfamilies (55% of the total subfamilies recorded in the world). Interestingly, these two subfamilies were not collected from the PFR UKM located only 15 km away from AHFR although studies at PFR-UKM was conducted for almost three consecutive years (Idris 2000, Hasnah 1999). This indicates that AHFR has plants and food sources that support the insect hosts of Adelognathinae and Orthopelmatinae as well as the parasitoids.
There was a significant difference in the number of species and total individuals of ichneumonids or braconids collected among
44 PERTANlKAJ. TROP. AGRIC. SCI. VOL. 24 NO. 1,2001
PRELIMINARY STUDY ON DIVERSITY AND ABUNDANCE OF OCHNEUMONIDS AND BRACONIDS
TABLE 1 List of Ichneumonidae collected from Ayer Hitam Forest Reserve, UPM
Cremastinae
Adelognathinae
Morphospecies Number of Individuals
1 1 10 1 14 3 16 3 17 1 18 1 19 4 21 1 22 8
2 I 3 1 4 1 5 1 6 1 7 1 8 1 9 1
11 1 12 1 13 1 15 5 19 1 20 1 21 4 22 13
21 3
6
2
1 1 2 5 3 4
2
a I, Inner, II (middle), III (near forest fringes)
PERTANIKAJ. TROP. AGRIC. SCI. VOL. 24 NO.1, 2001 45
lORIS, A.B, SAJAP, A. S, NOOR FARIKHA, H., YAAKOB, A. Band M. Y RUSLAN
TABLE 2 List of Braconidae collected at Ayer Hitam Forest Reserve, UPM
Subfamily
Agathidinae
Rogadinae
Microgastrinae
Agathidinae
a I, Inner, II (middle), III(near forest fringes)
sampling points (:{l = 22.3 or 15.3, df = 2) (Tables 1 and 2). Both parasitoid populations tend to be lower at the forest fringes than in the middle (Tables 1 and 2). This is probably due to the abundance of insect hosts and food sources which increases from the forest fringe towards the interior forest. The ground-dwelling insects in AHFR were also found to be more abundant in the middle of the forest (Sajap et. al. 1999). In Sulawesi, Indonesia, parasitic hymenopterans are more abundant along the forest edge than in the inner forest (Noyes 1989). This was said to be due to plenty of nectar sources along the forest edge as compared to the inner forest.
Diversity
The diversity (Shannon index, H') for ichneu monid and braconid species is shown in Table 3. For ichneumonid species, H' was significantly
higher (P < 0.05) at the sampling points 'I' (innermost) and 'II' (middle) than at the sampling point 'III' (forest fringes). In contrast, the braconid species was significantly more diverse at 'II' (H' = 2.45) than at 'I' (H' = 1.07) or 'II' (H' = 0). Generally, species diversity is influenced by the combination of two important factors i.e., the species evenness (E) and species richness (R) (Pielou 1975). However, our results suggest that 'E' plays a more important role in determining diversity than that of 'R'. As shown in Table 3, the ichneumonid species was less abundant at sampling point 'I' (R = 4.09) than at 'II' (R = 6.07) but its evenness was just slightly higher at 'I' (E = 0.89) than at II (0.86). Similarly for the braconids, the low H' value at 'I' may due to the low E rather than R value. There was no H' value for braconid species at 'III'. This was simply due to only one species or individual collected. Higher diversity in the middle of the
46 PERTANIKAJ. TROP. AGRIC. SCI. VOL. 24 NO. 1, 2001
PRELIMINARY STUDY ON DIVERSITY AND ABUNDANCE OF OCHNEUMONIDS AND BRACONIDS
TABLE 3 Shannon index for species diversity (H'), evenness (E) and Margalefs index (richness, R) among plots for Ichneumonids and Braconids collected from Ayer Hitam Forest Reserve
Family Sampling H' E R Poine
Ichneumonids I 2.49a 0.89 4.09 II 2.76a 0.86 6.07 III 0.56b 0.81 0.72
Braconidae I 1.07b 0.77 2.44 II 2.45c 0.95 4.15 III Oa 0.00 0.00
a I, Inner, II (middle), III (near forest fringes). In Column, the H' values with same letters are not significantly different (paired t-test, P > 0.05)
AHFR than in the forest fringes is expected as availability of life support resources (insect hosts and food/nectar sources) are more in the middle than in forest fringes. As discussed in the 'abundance' section above, the resource availability in the interior than at the edge of AHFR may playa big role in determining the H' value of the parasitoids. The abundance of insect hosts and food sources are important for the life and reproduction of most parasitic Hymenoptera such as ichneumonid and braconids (Jervis and Kidd 1996, Jervis et al, 1993). Sajap et al, (l999) also reported that the diversity of ground-dwelling insects increases from the forest fringes toward the centre of the forest.
It is interesting to note that H' of braconids at T was significantly less diverse than at 'II' (Table 3). Unlike ichneumonids, the braconids are generalist parasitoids, and most probably they have high numbers of insect host species available around point 'II' than point T. The specialist parasitoids such as ichneumonids are very mobile and actively find its hosts that are scattered in the landscape or forest (Hawkin and Sheehan 1994). Therefore, they have a higher probability of being trapped than the braconids.
CONCLUSION
Results of our preliminary study indicated that AHFR has diverse ichneumonid and braconid species. AHFR currently acts as a refuge for many animals including insects nearby that are adversely affected by loss of habitats due to forest destruction and fragmentation. However, the current diversity of these parasitoids may decline if their life supports' resources continue
to deplete as a result of forest disturbances. The longevity and fecundity of many parasitoids is highly correlated with the availability of nectar sources (Idris and Grafius 1995). The on-going and future projects such as housing estates and infrastructure construction occurring around the AHFR may also change the forest environmen t conditions that may be unfavorable to the ichneumonids and braconids, their insect hosts and associated food plants.
It is expected that more insects will be collected if the experiment is prolonged for at least a year. By so doing, information on the distribution pattern and presence of some new species could be recorded. This information may help us to understand which species may be a keystone species, endemic to AHFR or useful to be used as an indicator of habitat disturbance. Since Adelognathinae and Orthopelmatinae species have only been recorded in temperate areas, it is worthwhile to further investigate these taxa together with their hosts and plants that associate with them.
ACKNOWLEDGEMENT
We are grateful to the Faculty of Forestry, Universiti Putra Malaysia for allowing us to conduct the study in AHFR. Many thanks to Mrs Nor Azura and Ms Normala, Faculty of Science and Technology, Universiti Kebangsaan Malaysia for their assistance in the laboratory. This study was funded by IRPA grants 09-02-02 022 and 09-02-02-0170.
REFERENCES
HASNAH, T. 1999. Kepelbagaian Ichneumonidae di habitat berbeza di Malaysia. B.Se. Thesis, UKM (unpublished).
PERTANIKAJ. TROP. AGRIC. SCI. VOL. 24 NO. 1,2001 47
IDRIS, A.B, SAJAP, A. S, NOOR FARIKHA, H., YAAKOB, A. Band M. Y RUSlAN
HAWKIN, B. A. and W. SHEEHAN. 1994. Parasitoid Community Ecology, 516 p. Oxford University
Press.
IDRIs, A.B. 1996b. Kajian kepelbagaian serangga Hymenoptera dengan penumpuan khas kepada Hymenoptera Parasitika di Hutan Simpan Kekal Universiti Kebangsaan Malay sia. Technical Report. UKM B/6/96. 44 p.
IDRJS A. B. 2000. A comparative study on the abundance and diversity of Ichneumonid wasps (Hymenoptera: Ichneumonidae) in selected forest and non-forest habitats in Peninsular Malaysia. Joumal of Biosciences (In press).
IDRJS, A. and E. GRAFlus. 1995. Wildflowers as nectar sources for Diadegma insulare (Hymenoptera: Ichneumonidae). a parasitoid of diamondback moth (Lepidoptera: Yponomeutidae). Environ mental Entomology 24(6): 1726-1735.
IDRJs, A. B. and A. NOR AzURA. 1998. Comparative study on methods of collecting parasitic hymenoptera with special emphasis on the family of Ichneumonidae. Malaysian Applied Biology 27: 87-94.
JERVIS, M.A. and N.A.C. KIDD. 1996. Insect Natural Enemies. Practical Approaches to their Study and Evaluation. 491 p. London: Chapman & Hall.
JERVIS, M.A., N.A.C. KIDD, M.G. FITTON, T. HUDDLESTON, and H.A. DAWAH. 1993. Flower visiting by hymenopteran parasitoids. Jumal of Natural History 27: 67 - 105.
LA SALLE, J. and !. D. GAULD, 1993. Hymenoptera and Biodiversity, 384 p. CAB!.
MOHAMED ZAKARIA and RAHMAT TOPANI. 1999. Abundance of primates in Ayer Hitam Forest, Puchong. Selangor. PertanikaJournal of Tropical Agriculture Science 22(2): 105-109.
NOR AzURA, A. and A. B. IDRJs. 1998. Comparative study on diversity of Ichneumonidae in disturbed and undisturbed forest. Malaysian Applied Biology 27: 95-98.
No'rES, J.S. 1989. The diversity of Hymenoptera in the ropics with special references to Parasitika in Sulawesi. Ecological Entomology 14: 197-207.
PIELOU, E. C. 1975. Ecological Diversity, 165 p. New York: John Wiley and Sons.
ROBINSON, G. S. 1991. Alpha, PC Version GW Basic. London: Natural History Museum.
SAJAP, A.S., A.R. ROZITA. H. NOOR FARIKHA and AW. YMKOB 1999. Diversity of ground-dwelling insects in Ayer Hitam Forest Reserve. Pertanika Journal of Tropikal Agriculture Sciences 22(2): 207-298
TOWNES, H. and S. C. CHIU. 1970. The indo Australian species ofXanthopimpla (Ichneu monidae). Mem. Amer. Ent. Inst. No. 14.372 p.
WAHL, D. B. andJ. S. SHARKEY. 1993. Superfamily Ichneumonoidea. In Hymenoptera ofthe World: An Identification Guide to Family, ed. H. Goulet & J. T. Huber, p. 358 - 499. Canada: Publication 1894/E.
48 PERTANlKAJ. TROP. AGRIe. SCI. VOL. 24 NO.1, 2001
Preliminary Study on Diversity and Abundance of Ichneumonids and Braconids (Insecta: Hymenoptera) at
the Ayer Hitam Forest Reserve
IDRIS, A.lll, SAJAP, A. S~, NOOR FARIKHA, H~., YAAKOB, A. B~ and M. Y RUSI.AN~
I School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
2Faculty of Forestry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
Keywords: Diversity, abundance, Hymenoptera, Ayer Hitam Forest Reserve
ABSTRAK
Satu kajian awal tentang kepelbagaian dan kelimpahan ichneumonid dan braconid (Insecta: Hymenoptera) di Hutan Simpan Ayer Hitam (AHFR), Universiti Putra Malaysia telah dij'alankan dari 4 - 11 April 2000. Hasil kajian ini menunjukkan bahawa AHFR didiami oleh pelbagai spesies ichneumonid dan braconid. Secam keseluruhannya, didapati bahawa spesies ichneumonid adalah hampir dua kali lebih melimpah dan pelbagai berbanding braconid. Walau bagaimanapun, kedua-dua kumpulan serangga ini mempunyai kepelbagaian spesies yang lebih tinggi dan signijikan di bahagian tengah hutan berbanding di kawasan pinggir hutan. Dua lagi tambahan subfamili ichneumonid (Adelognathinae dan Orthopelmatinae) untuk Malaysia Lelah ditemui dari hutan ini.
ABSTRACT
A preliminary study on diversity and abundance of ichneumonids and braconids (Insecta: Hymenoptera) oj Ayer Hitam Forest Reserve (AHFR) oj Universiti Putra Malaysia was conducted Jrom 4 - 11 April 2000. Results showed that AHFR houses a variety oj ichneumonid and braconid species. Generally, the ichneumonids were nearly twice as abundant and diverse than braconids. However, both insect groups were signijicantly more diverse in the middle than in the Jorest fringes. Two more additions of ichneumonid subJamilies (Adelognathinae and Orthopelmatinae) for Malaysia were discovered from this Jorest.
INTRODUCTION
Insects are the most abundant animals on earth and two-thirds of insects inhabit the tropical rain forest. In Peninsular Malaysia, majority of these insects occupy the lowland forests. These forests provide habitats for thousands of insect species that are functionally important to the forest ecosystems. Insects can be pollinators, decomposers, herbivores, predators or para sitoids. Most parasitoids are in the order of Hymenoptera. They use or parasitize other insects for reproduction. As such, they are important regulators of other insect populations, mostly herbivores feeding on various parts of plants.
In recent years however, the rate of deforestation in the lowland forests is rather
alarming. The destruction of natural habitats due to logging and development pose the greatest threat to insect communities in the forests. Since the parasitoid reproduction depends on other insects, their own population and role will be severely affected by the reduction of host population as a consequent of habitat destruction. In view of the changing ecosystem of Ayer Hitam Forest Reserve and its vicinity, a study on the diversity of Ichneumonids and Braconids, the two important group of parasitic Hymenoptera was conducted. Presently, scanty information is available on these in Malaysia except those of Idris (1996a and 1996b), Idris and Nur Azura (1998) and Nor Azura and Idris (1998) .
IDRIS, A.B, SAJAP, A. S, NOOR FARIKHA, H., YAAKOB, A. Band M. Y RUSlAN
MATERIALS AND METHODS
The study was conducted at Ayer Hitam Forest Reserve (AHFR) , Puchong, Selangor, about 20 km southwest of Kuala Lumpur and 6 km from Universiti Putra Malaysia (UPM), Serdang Campus, Selangor, Malaysia, at latitudes between 20· 57' N to 30· 04' N and longitudes 101· 38'E to 101· 41'E. The AHFR is an undulating lowland dipterocarp forest ranging from 15 m to 157 m above sea level, managed as a forest reserve by the Forest Office of Central Selangor and was selectively logged between 1936 and 1965 (Mohamad Zakaria and Rahmat Topani 1999). The study sites were located within compartments 1, 2, 12, 13, 14 and 15 of AHFR that has been leased to UPM for 80 years under an agreemen t between Universiti Putra Malaysia and the state government of Selangor.
Two transects were established within the compartments, both were parallel to each other and 200 m apart. There were three sampling points (= treatments) chosen along each transect across the compartments viz., two each at both ends and one in middle. The distance between the points was between 200 and 250 m, and 30 - 50 m from the outer sampling point to forest edge. A total of six malaise traps were used and one trap was placed at each sampling point beginning 4 until 11 September 2000. Traps were left in the forest for eight days before insects were collected and brough t to the laboratory for sorting and identification. The specimen identification was made based on Wahl and Sharkey (1993) and Townes and Chiu (1970).
In reducing error and getting a more representative data, the insects collected from similar sampling point of two transects were pooled before analysis. Data were analyzed using GW Basic program to get differential species diversity between sampling points (Robinson, 1991) while X2 was used to analyze differences in species and individual abundance among sampling points
RESULTS AND DISCUSSION
Abundance
The ichneumonids and braconids collected are shown in Tables 1 and 2. There were eight ichneumonid subfamilies collected viz., Cryptinae, Anomaloninae, Cremastinae, Adelognathinae, Diplazontinae, Orthopelma-
tinae, Pimplinae, Collyriinae and the seven braconid subfamilies include Agathidinae, Rogadinae, Microgastrinae, Gnamptodontinae, Opiinae, Cheloninae and Doryctinae. A total of 38 morphospecies and 95 individual ichneumonids were collected. The braconids on the other hand had only 14 morphospecies and 27 individuals (Table 2),3 - 4 times less abundant than ichneumonid. Braconids also seemed to be less abundant than ichneumonids in the Permanent Forest Reserve of Universiti Kebangsaan Malaysia (PFR-UKM) (ldris 1996b). As such, results of this study tend to disagree wi th universal claim that in tropical regions braconids are more abundant than ichneumonids (Noyes 1989, La Salle and Gauld 1993).
Of the eight ichneumonid subfamilies collected, the cryptine had the most numbers of morphospecies (22) and individuals (58) as compared with other subfamilies and morpho species numbered 22, seemed to be the most abundant in AHFR (Table 1). This tends to agree with what was reported by Wahl and Sharkey (1993) as the majority of cryptine species are generalist and/or idiobiont parasitoid having wide host ranges irrespective of habitats. The morpho-species numbered 21 (Table 1) seemed to occur at all sampling points, indicating they are the least group that could be severely affected by habitat disturbances. As for braconids, however, no single subfamily seemed to have more number ofmorphpospecies over the others (Table 2). This indicates that AHFR does not have much resource to support braconid populations.
Although the collection was made for a period of one week, this study was successful in adding two more ichneumonid subfamilies for Malaysia, Le., Adelognathinae and Ortho pelmatinae, from 18 as listed by Idris (2000) to 20 subfamilies (55% of the total subfamilies recorded in the world). Interestingly, these two subfamilies were not collected from the PFR UKM located only 15 km away from AHFR although studies at PFR-UKM was conducted for almost three consecutive years (Idris 2000, Hasnah 1999). This indicates that AHFR has plants and food sources that support the insect hosts of Adelognathinae and Orthopelmatinae as well as the parasitoids.
There was a significant difference in the number of species and total individuals of ichneumonids or braconids collected among
44 PERTANlKAJ. TROP. AGRIC. SCI. VOL. 24 NO. 1,2001
PRELIMINARY STUDY ON DIVERSITY AND ABUNDANCE OF OCHNEUMONIDS AND BRACONIDS
TABLE 1 List of Ichneumonidae collected from Ayer Hitam Forest Reserve, UPM
Cremastinae
Adelognathinae
Morphospecies Number of Individuals
1 1 10 1 14 3 16 3 17 1 18 1 19 4 21 1 22 8
2 I 3 1 4 1 5 1 6 1 7 1 8 1 9 1
11 1 12 1 13 1 15 5 19 1 20 1 21 4 22 13
21 3
6
2
1 1 2 5 3 4
2
a I, Inner, II (middle), III (near forest fringes)
PERTANIKAJ. TROP. AGRIC. SCI. VOL. 24 NO.1, 2001 45
lORIS, A.B, SAJAP, A. S, NOOR FARIKHA, H., YAAKOB, A. Band M. Y RUSLAN
TABLE 2 List of Braconidae collected at Ayer Hitam Forest Reserve, UPM
Subfamily
Agathidinae
Rogadinae
Microgastrinae
Agathidinae
a I, Inner, II (middle), III(near forest fringes)
sampling points (:{l = 22.3 or 15.3, df = 2) (Tables 1 and 2). Both parasitoid populations tend to be lower at the forest fringes than in the middle (Tables 1 and 2). This is probably due to the abundance of insect hosts and food sources which increases from the forest fringe towards the interior forest. The ground-dwelling insects in AHFR were also found to be more abundant in the middle of the forest (Sajap et. al. 1999). In Sulawesi, Indonesia, parasitic hymenopterans are more abundant along the forest edge than in the inner forest (Noyes 1989). This was said to be due to plenty of nectar sources along the forest edge as compared to the inner forest.
Diversity
The diversity (Shannon index, H') for ichneu monid and braconid species is shown in Table 3. For ichneumonid species, H' was significantly
higher (P < 0.05) at the sampling points 'I' (innermost) and 'II' (middle) than at the sampling point 'III' (forest fringes). In contrast, the braconid species was significantly more diverse at 'II' (H' = 2.45) than at 'I' (H' = 1.07) or 'II' (H' = 0). Generally, species diversity is influenced by the combination of two important factors i.e., the species evenness (E) and species richness (R) (Pielou 1975). However, our results suggest that 'E' plays a more important role in determining diversity than that of 'R'. As shown in Table 3, the ichneumonid species was less abundant at sampling point 'I' (R = 4.09) than at 'II' (R = 6.07) but its evenness was just slightly higher at 'I' (E = 0.89) than at II (0.86). Similarly for the braconids, the low H' value at 'I' may due to the low E rather than R value. There was no H' value for braconid species at 'III'. This was simply due to only one species or individual collected. Higher diversity in the middle of the
46 PERTANIKAJ. TROP. AGRIC. SCI. VOL. 24 NO. 1, 2001
PRELIMINARY STUDY ON DIVERSITY AND ABUNDANCE OF OCHNEUMONIDS AND BRACONIDS
TABLE 3 Shannon index for species diversity (H'), evenness (E) and Margalefs index (richness, R) among plots for Ichneumonids and Braconids collected from Ayer Hitam Forest Reserve
Family Sampling H' E R Poine
Ichneumonids I 2.49a 0.89 4.09 II 2.76a 0.86 6.07 III 0.56b 0.81 0.72
Braconidae I 1.07b 0.77 2.44 II 2.45c 0.95 4.15 III Oa 0.00 0.00
a I, Inner, II (middle), III (near forest fringes). In Column, the H' values with same letters are not significantly different (paired t-test, P > 0.05)
AHFR than in the forest fringes is expected as availability of life support resources (insect hosts and food/nectar sources) are more in the middle than in forest fringes. As discussed in the 'abundance' section above, the resource availability in the interior than at the edge of AHFR may playa big role in determining the H' value of the parasitoids. The abundance of insect hosts and food sources are important for the life and reproduction of most parasitic Hymenoptera such as ichneumonid and braconids (Jervis and Kidd 1996, Jervis et al, 1993). Sajap et al, (l999) also reported that the diversity of ground-dwelling insects increases from the forest fringes toward the centre of the forest.
It is interesting to note that H' of braconids at T was significantly less diverse than at 'II' (Table 3). Unlike ichneumonids, the braconids are generalist parasitoids, and most probably they have high numbers of insect host species available around point 'II' than point T. The specialist parasitoids such as ichneumonids are very mobile and actively find its hosts that are scattered in the landscape or forest (Hawkin and Sheehan 1994). Therefore, they have a higher probability of being trapped than the braconids.
CONCLUSION
Results of our preliminary study indicated that AHFR has diverse ichneumonid and braconid species. AHFR currently acts as a refuge for many animals including insects nearby that are adversely affected by loss of habitats due to forest destruction and fragmentation. However, the current diversity of these parasitoids may decline if their life supports' resources continue
to deplete as a result of forest disturbances. The longevity and fecundity of many parasitoids is highly correlated with the availability of nectar sources (Idris and Grafius 1995). The on-going and future projects such as housing estates and infrastructure construction occurring around the AHFR may also change the forest environmen t conditions that may be unfavorable to the ichneumonids and braconids, their insect hosts and associated food plants.
It is expected that more insects will be collected if the experiment is prolonged for at least a year. By so doing, information on the distribution pattern and presence of some new species could be recorded. This information may help us to understand which species may be a keystone species, endemic to AHFR or useful to be used as an indicator of habitat disturbance. Since Adelognathinae and Orthopelmatinae species have only been recorded in temperate areas, it is worthwhile to further investigate these taxa together with their hosts and plants that associate with them.
ACKNOWLEDGEMENT
We are grateful to the Faculty of Forestry, Universiti Putra Malaysia for allowing us to conduct the study in AHFR. Many thanks to Mrs Nor Azura and Ms Normala, Faculty of Science and Technology, Universiti Kebangsaan Malaysia for their assistance in the laboratory. This study was funded by IRPA grants 09-02-02 022 and 09-02-02-0170.
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